A variety of high temperature insulating structures have been proposed for use in the heavy metals industries, e.g., the steel industry. As an example, an insulation container adapted for placement over a hot metal ingot has been proposed in U.S. Pat. No. 4,168,013. The container comprises inner and outer walls which are spaced apart for containing insulation. The insulation comprises layers of thin, reflective radiation foil shields which are themselves spaced apart by fibrous ceramic layers.
In a contemporaneous development, ingot molds can be fabricated to have layered upper sections. The upper, inner wall is formed from a plate of material capable of withstanding hot metal contact. This inner wall is spaced apart from the wall of the mold. Then, as discussed in International patent application No. PCT/EP80/00131 the interior space can be filled with a compressible insulation filler such as a ceramic fiber insulation.
In pit-type heat soaking of ingots, cover structures have been proposed which employ mats of ceramic fiber insulating material. Thus in U.S. Pat. No. 4,411,621 it has been shown to support such fibrous mats by securing them to a metal mesh cover, such as by wire ties. The structure can find use as a furnace wall or soaking pit cover.
It has also been proposed to cover bottle type ladle cars by the use of ceramic fiber blankets that are covered, top and bottom, by metal mesh. Fasteners are positioned through the blankets and secure the opposing metal mesh covers one with the other. The resulting structure can then be fastened to the open top of a bottle type ladle car, such as by wire ties.
It has heretofore been proposed to cover hot ladles using a lid with metal mesh just on top. The opposing surface of such cover is simply ceramic fiber. The fiber is in two layers, with the top layer being secured to the top metal mesh. The lower fiber layer is mortar-bonded to the upper layer to provide for a well sealed ladle cover. Rigid ceramic legs within the fiber can be useful for supporting the cover structure on the ladle.
It would however be most desirable to assemble a cover structure having sufficient strength and durability for repeated mill use. It would also be most desirable if such a structure provided not only ease of assembly, but also ease of repair. It would also be highly advantageous to have the structure resistant to deleterious degradation of its fiber elements, such as can accompany the offgassing of container contents. It would furthermore be advantageous if such cover structure could be easily placed upon and removed from the container.